Toomre Q parameter estimated as a function of radius for the initial disk galaxies in a 4:1 merger in ramses. A horizontal line marks the marginally stable value Q = 1. At a gas temperature of 10³ K (which is effectively enforced by the Jeans polytrope temperature minimum), the secondary galaxy is substantially more stable than the primary, and it remains stable or near marginal stability at all radii. This leads to a low SFR in the secondary. In the gasoline simulations without a Jeans polytrope, the secondary has higher SFRs.